Palletizing apparatus are used to accept containers or packages from a source and load those containers or packages on a pallet for shipment or storage. The objects loaded on the pallet are loaded in several tiers, each tier assuming a specific pattern to maximize the amount of objects stored on the pallet, and to facilitate stability of the pallet, that is, to prevent objects from falling off the pallet when jarred or shaken.
Conventionally, palletizing apparatus utilize rollers energized from beneath by rubber belts to feed the objects to be palletized along the palletizer. However, when the objects to be palletized comprise packages of containers for beverages or the like, such as soda cans, the use of such rollers has been found extremely disadvantageous. Packages of soda cans or other like containers are formed by encasing the containers in a relatively thin cardboard package or enclosing the top of the containers in a plastic sheath. When such packaged containers are fed through a palletizer via rollers, damage to the containers and container packages caused by the gap between rollers often occurs, especially when high speed operation is desired. This results in extensive downtime and maintenance of the palletizer, as well as significant loss of product.
In addition, printed cardboard packaging contains waxes and inks, which may be transferred to the rollers by friction from the packages contacting the rollers. This can result in a build-up of waxes and inks on the rollers which can cause sliding of the packages on the rollers in a transverse direction (perpendicular to the desired direction of travel), leading to misalignment of container packages. Moreover, transverse sliding can cause the packages to strike the frame of the palletizer, potentially damaging the packages, the individual containers, and the palletizer. This results in significant downtime and product loss. Although it is possible to form rollers of a material resistant to build up of waxes and inks, such as polytetrafluoroethylene, commercially available as Teflon brand material, this has been found to be commercially unfeasible because of the costs involved.
These problems are not usually encountered when unpackaged containers are palletized, because of the hardness and non-marking of the bottom of such containers. However, when packaged containers are palletized, problems ensue. Because of these disadvantages, conventional palletizers do not handle packaged products with a desired efficiency, nor do they have the capability of handling diverse product lines.
It would be desirable to provide a palletizing apparatus which is capable of transporting container packages and loading them on a pallet in a desired pattern in a high speed fashion, while eliminating the downtime and product loss associated with the use of roller conveyors.